Camera Labs

DVD's don't get viruses. HDD do. 1 bad virus and bye bye forever to your pictures!

You don't have a single copy on a single HD. You would have a copy on the computer, and another copy on a removable disk. The risk of a virus wiping both out is minimal providing you take reasonable care not to get viruses in the first place.

_________________
Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.

This is why I don't use Raid: Viruses and delete-operations just wipe both HDs at once. If you do time-based backup (e.g. once a week) you have a grace-period before desaster can strike at your backup disk.

_________________
Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews, My Pictures, My Photography Blog
D800+assorted lenses